Now we're talking! I love boxing cabinets. Since you two started with The Great John L., I will throw my hat in the ring with these:
Not really hard cards but the image clarity made each a keeper for me:
1882 Mora, one of his earliest cards, pirated frequently over the next 15 or so years:
Now some may be saying that doesn't really look like Sullivan and his name isn't on the mount, so how do I know it is him? Well, here are two vintage pieces, an ad for a Sullivan statue and a publication:
The Sullivan statuette ad is on the back of this card:
It shows Sullivan as a young fighter. It appears to me to be a pirate issue based on an early photo.
Happy as heck to get a front-signed one:
One of these days I will have to pare down to one card. The signed one makes sense but this English CDV is actually my favorite image:
I'm getting more into CDVs because they are easier to store. A nice mylar in a four-pocket page.